U.S. patent number 10,756,686 [Application Number 16/595,498] was granted by the patent office on 2020-08-25 for band sharing technique of receiver.
This patent grant is currently assigned to MEDIATEK INC.. The grantee listed for this patent is MEDIATEK INC.. Invention is credited to Yi-Bin Lee, Yu-Tsung Lo, Chih-Hao Sun.
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United States Patent |
10,756,686 |
Sun , et al. |
August 25, 2020 |
Band sharing technique of receiver
Abstract
The present invention provides a receiver including a first band
group, a second band group and a mixer. The first band group
includes at least one LNA, wherein the first band group is
configured to select one first LNA to receive a first input signal
to generate an amplified first input signal. The second band group
includes at least one LNA, wherein the second band group is
configured to select one second LNA to receive a second input
signal to generate an amplified second input signal. The first band
group and the second band group are coupled to a first input
terminal and a second input terminal of the mixer, respectively,
and the mixer receives one of the amplified first input signal and
the amplified second input signal to generate an output signal.
Inventors: |
Sun; Chih-Hao (Hsin-Chu,
TW), Lo; Yu-Tsung (Hsin-Chu, TW), Lee;
Yi-Bin (Hsin-Chu, TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
MEDIATEK INC. |
Hsin-Chu |
N/A |
TW |
|
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Assignee: |
MEDIATEK INC. (Hsin-Chu,
TW)
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Family
ID: |
68296325 |
Appl.
No.: |
16/595,498 |
Filed: |
October 8, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200144975 A1 |
May 7, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62756611 |
Nov 7, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03F
3/72 (20130101); H03D 7/1458 (20130101); H04B
1/005 (20130101); H03F 3/193 (20130101); H03D
7/1441 (20130101); H04B 1/0082 (20130101); H03F
2200/294 (20130101); H03F 2200/451 (20130101); H03F
2200/372 (20130101) |
Current International
Class: |
H04B
1/10 (20060101); H04B 1/16 (20060101); H03F
3/72 (20060101); H03D 7/14 (20060101); H03F
3/193 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 917 297 |
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May 1999 |
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EP |
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0 917 297 |
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Mar 2003 |
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EP |
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1 394 957 |
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Mar 2004 |
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EP |
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Other References
Tzung-Han Wu, "A 40nm 4-downlink and 2-uplink RF Transceiver
Supporting LTE-Advanced Carrier Aggregation", 2018 IEEE Radio
Frequency Integrated Circuits Symposium. cited by
applicant.
|
Primary Examiner: Jackson; Blane J
Attorney, Agent or Firm: Hsu; Winston
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority of U.S. Provisional
Application No. 62/756,611, filed on Nov. 7, 2018, which is
included herein by reference in its entirety.
Claims
What is claimed is:
1. A receiver, comprising: a first band group comprising at least
one first low-noise amplifier (LNA), wherein the first band group
is configured to select one first LNA to receive a first input
signal to generate an amplified first input signal; a second band
group comprising at least one second LNA, wherein the second band
group is configured to select one second LNA to receive a second
input signal to generate an amplified second input signal; and a
mixer, wherein the first band group and the second band group are
coupled to a first input terminal and a second input terminal of
the mixer, respectively, and the mixer receives one of the
amplified first input signal and the amplified second input signal
to generate an output signal.
2. The receiver of claim 1, further comprising: a first switch,
coupled between the first band group and the first input terminal
of the mixer; and a second switch, coupled between the second band
group and the second input terminal of the mixer; wherein only one
of the first switch and the second switch is enabled to transmit
the amplified first input signal or the amplified second input
signal to the mixer.
3. The receiver of claim 2, further comprising: a first capacitor,
coupled between the first switch and the first input terminal of
the mixer.
4. The receiver of claim 3, further comprising: a second capacitor,
coupled between the second switch and the second input terminal of
the mixer.
5. The receiver of claim 3, further comprising: a second capacitor,
coupled between the second band group and the second switch.
6. The receiver of claim 2, further comprising: a first capacitor,
coupled between the first band group and the first switch.
7. The receiver of claim 6, further comprising: a second capacitor,
coupled between the second band group and the second switch.
8. The receiver of claim 1, further comprising: a first load,
coupled to an output terminal of the first band group; and a first
switch, coupled between a supply voltage and the first load, for
selectively connecting the supply voltage to the first load or
not.
9. The receiver of claim 8, further comprising: a second load,
coupled to an output terminal of the second band group; and a
second switch, coupled between the supply voltage and the second
load, for selectively connecting the supply voltage to the second
load or not.
10. The receiver of claim 1, wherein the mixer is a double balance
mixer comprising: a first control switch, for selectively
connecting the first input terminal of the mixer to a first output
terminal of the mixer according to an oscillation signal; a second
control switch, for selectively connecting the first input terminal
of the mixer to a second output terminal of the mixer according to
another oscillation signal; a third control switch, for selectively
connecting the second input terminal of the mixer to the first
output terminal of the mixer according to the another oscillation
signal; and a fourth control switch, for selectively connecting the
second input terminal of the mixer to the second output terminal of
the mixer according to the oscillation signal.
11. The receiver of claim 10, further comprising: a first switch,
coupled between the first band group and the first input terminal
of the mixer; and a second switch, coupled between the second band
group and the second input terminal of the mixer; wherein only one
of the first switch and the second switch is enabled to transmit
the amplified first input signal or the amplified second input
signal to the mixer.
12. The receiver of claim 1, wherein the mixer comprises a double
balanced mixer.
Description
BACKGROUND
In the conventional receiver, each band group needs a dedicated
mixer and operates independently. To decrease the chip area, some
mixer sharing techniques are provided. In a first example, two band
groups are coupled to an input terminal of the mixer via switches,
respectively, and only one of the band groups is allowed to connect
to the input terminal of the mixer at the same time. However, the
switches of the first example provide additional parasitic load,
and the input terminal of the mixer will see the parasitic load of
two switches. In a second example, two band groups are directly
connected to the input terminal of the mixer, and only one of the
band groups is enabled to transmit a signal to the input terminal
of the mixer at the same time. However, the load of the band groups
needs to be co-designed, and the input terminal of the mixer will
see the parasitic load of two band groups, causing a worse
performance of the receiver.
SUMMARY
It is therefore an objective of the present invention to provide a
band sharing technique, wherein the mixer shared by two band groups
has lower load at the input terminal, to solve the above-mentioned
problem.
According to one embodiment of the present invention, a receiver
comprising a first band group, a second band group and a mixer is
provided. The first band group comprises at least one first
low-noise amplifier (LNA), wherein the first band group is
configured to select one first LNA to receive a first input signal
to generate an amplified first input signal. The second band group
comprises at least one second LNA, wherein the second band group is
configured to select one second LNA to receive a second input
signal to generate an amplified second input signal. The first band
group and the second band group are coupled to a first input
terminal and a second input terminal of the mixer, respectively,
and the mixer receives one of the amplified first input signal and
the amplified second input signal to generate an output signal.
These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading
the following detailed description of the preferred embodiment that
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating a receiver according to one
embodiment of the present invention.
FIG. 2 shows that the first band group is selected in the receiver
shown in FIG. 1.
FIG. 3 shows that the second band group is selected in the receiver
shown in FIG. 1.
FIG. 4 is a diagram illustrating a receiver according to another
embodiment of the present invention.
FIG. 5 shows that the first band group is selected in the receiver
shown in FIG. 4.
FIG. 6 shows that the second band group is selected in the receiver
shown in FIG. 4.
FIG. 7 is a diagram illustrating a double balanced mixer according
to one embodiment of the present invention.
DETAILED DESCRIPTION
Certain terms are used throughout the following description and
claims to refer to particular system components. As one skilled in
the art will appreciate, manufacturers may refer to a component by
different names. This document does not intend to distinguish
between components that differ in name but not function. In the
following discussion and in the claims, the terms "including" and
"comprising" are used in an open-ended fashion, and thus should be
interpreted to mean "including, but not limited to . . . ". The
terms "couple" and "couples" are intended to mean either an
indirect or a direct electrical connection. Thus, if a first device
couples to a second device, that connection may be through a direct
electrical connection, or through an indirect electrical connection
via other devices and connections.
FIG. 1 is a diagram illustrating a receiver 100 according to one
embodiment of the present invention. As shown in FIG. 1, the
receiver 100 comprises a first band group 110, a second band group
120 and double balanced mixers 130 and 140, wherein the first band
group 110 comprises at least one LNA (in this embodiment, the first
band group 110 comprises a plurality of LNAs 112_1-112_M), and the
second band group 120 comprises at least one LNA (in this
embodiment, the second band group 120 comprises a plurality of LNAs
122_1-122_N), and M and N can be any suitable values. In addition,
the first band group 110 has a first load 114 at an output
terminal, and a first switch SW1 and a first capacitor C1 are
coupled between the first band group 110 and first input terminals
of the double balanced mixers 130 and 140; and the second band
group 120 has a second load 124 at an output terminal, and a second
switch SW2 and a second capacitor C2 are coupled between the second
band group 120 and second input terminals of the double balanced
mixers 130 and 140.
In the operations of the receiver 100, only one of the first band
group 110 and the second band group 120 is selected to connect to
the double balanced mixer 130. When the first band group 110 is
selected as shown in FIG. 2, the first switch SW1 is on and the
second switch SW2 is off, and the first band group 110 selects one
of the LNAs 112_1-112_M to receive a first input signal Vin1 to
generate an amplified first input signal Vin1', and the amplified
first input signal Vin1' passes through the first switch SW1 and
the first capacitor C1 to the first input terminal of the double
balanced mixer 130, and the double balanced mixer 130 mixes the
amplified first input signal Vin1' with an oscillation signal LOI
to generate an output signal VoutI; in addition, the double
balanced mixer 140 mixes the amplified first input signal Vin1'
with an oscillation signal LOQ to generate an output signal VoutQ.
In addition, when the second band group 120 is selected as shown in
FIG. 3, the second switch SW2 is on and the first switch SW1 is
off, and the second band group 120 selects one of the LNAs
122_1-122_N to receive a second input signal Vin2 to generate an
amplified second input signal Vin2', and the amplified second input
signal Vin2' passes through the second switch SW2 and the second
capacitor C2 to the second input terminal of the double balanced
mixer 130, and the double balanced mixer 130 mixes the amplified
second input signal Vin2' with the oscillation signal LOI to
generate the output signal VoutI; and the double balanced mixer 140
mixes the amplified second input signal Vin2' with an oscillation
signal LOQ to generate the output signal VoutQ.
In the embodiment shown in FIGS. 1-3, because each of the first
band group 110 and the second band group 120 uses only one input
terminal of the double balanced mixer 130 and only one input
terminal of the double balanced mixer 140, each signal path always
suffers the parasitic load of only one of the first switch SW1 and
the second switch SW2. Therefore, the signal quality is better than
the conventional art.
In addition, the capacitor C1 and the capacitor C2 are used to
prevent the bias voltage of the LNAs 112_1-112_M or 122_1-122_N
from being influenced by the bias voltage of the double balanced
mixer 130, that is the receiver 100 has better in-band
performance.
In another embodiment, the positions of the first switch SW1 and
the first capacitor C1 can be interchanged, or the positions of the
second switch SW2 and the second capacitor C2 can also be
interchanged, in order to make the double balanced mixer 130 has
less parasitic load at the input terminals (it is noted that the
parasitic load of the switch is much less than that of the
capacitor). Specifically, if the positions of the second switch SW2
and the second capacitor C2 are interchanged, when the first band
group 110 is enabled and the second band group 120 is disabled, the
second input terminal of the double balanced mixer 130 will see
less parasitic load and the second switch SW2 provides higher
impedance to the double balanced mixer 130, and the performance
regarding the double balanced mixer 130 processing the amplified
first input signal Vin1' will become better.
In light of above, because the positions of the first switch SW1
and the first capacitor C1 shown in FIGS. 1-3 makes the receiver
100 have better in-band performance, and the interchanged positions
of the second switch SW2 and the second capacitor C2 favors the
performance of the first band group 110, if the first band group
110 is more important than the second band group 120, the positions
of the second switch SW2 and the second capacitor C2 shown in FIGS.
1-3 can be interchanged to increase the performance of the first
band group 110.
FIG. 4 is a diagram illustrating a receiver 400 according to
another embodiment of the present invention. As shown in FIG. 4,
the receiver 400 comprises a first band group 410, a second band
group 420 and a double balanced mixer 430, wherein the first band
group 410 comprises a plurality of LNAs 412_1-412_M, and the second
band group 420 comprises a plurality of LNAs 422_1-422_N, and M and
N can be any suitable values. In addition, the first band group 410
has a first load 414 at an output terminal, and a first switch SW1
is coupled between a supply voltage VDD and the output terminal of
the first band group 410; and the second band group 420 has a
second load 424 at an output terminal, and a second switch SW2 is
coupled between the supply voltage VDD and the output terminal of
the second band group 420. It is noted that the receiver 400 may
further comprise another double balanced mixer as shown in FIG. 1,
where the double balanced mixer 430 is configured to generate an
in-phase output signal VoutI, and the other double balanced mixer
is configured to generate a quadrature output signal VoutQ, which
is similar to the embodiment shown in FIG. 1.
In the operations of the receiver 400, only one of the first band
group 410 and the second band group 420 are selected to connect to
the double balanced mixer 430. When the first band group 410 is
selected as shown in FIG. 5, the first switch SW1 is on and the
second switch SW2 is off, and the first band group 410 selects one
of the LNAs 412_1-412_M to receive a first input signal Vin1 to
generate an amplified first input signal Vin1', and the amplified
first input signal Vin1' enters the first input terminal of the
double balanced mixer 430, and the double balanced mixer 430 mixes
the amplified first input signal Vin1' with an oscillation signal
LO to generate an output signal Vout. In addition, when the second
band group 420 is selected as shown in FIG. 6, the second switch
SW2 is on and the first switch SW1 is off, and the second band
group 420 selects one of the LNAs 422_1-422_N to receive a second
input signal Vin2 to generate an amplified second input signal
Vin2', and the amplified second input signal Vin2' enters the
second input terminal of the double balanced mixer 430, and the
double balanced mixer 430 mixes the amplified second input signal
Vin2' with the oscillation signal to generate the output signal
Vout.
In the embodiment shown in FIGS. 4-6, because each of the first
band group 410 and the second band group 420 uses only one input
terminal of the double balanced mixer 430, the signal path always
suffers the parasitic load of only one of the first switch SW1 and
the second switch SW2. Therefore, the signal quality is better than
the conventional art.
FIG. 7 is a diagram illustrating a double balanced mixer 700
according to one embodiment of the present invention, wherein the
double balanced mixer 700 can be used to implement the double
balanced mixer 130/430. As shown in FIG. 7, the double balanced
mixer 700 comprises a first control switch M1, a second control
switch M2, a third control switch M3, a fourth control switch M4, a
first input terminal Nin1, a second input terminal Nin2, and two
output terminals Nout1 and Nout2, wherein the first control switch
M1 and the fourth control switch M4 are controlled by the
oscillation signal LO+, and the second control switch M2 and the
third control switch M3 are controlled by the oscillation signal
LO-. In this embodiment, the double balanced mixer 700 can be
regarded as a single balance mixer operation with the double
balanced circuit structure, that is the double balanced mixer 700
receives the input signal at only one of the input terminals to
generate a differential output signal. Specifically, in the
operations of the double balanced mixer 700, if the first band
group 110/410 is enabled, the double balanced mixer 700 receives
the amplified first input signal Vin1' from the first band group
110/410 to generate a differential output signal at the output
terminals Nout1 and Nout2 (at this time, the second input terminal
Nin2 is opened, that is the second input terminal Nin2 does not
receive any signal); and if the second band group 120/420 is
enabled, the double balanced mixer 700 receives the amplified
second input signal Vin2' from the first band group 120/420 to
generate the differential output signal at the output terminals
Nout1 and Nout2 (at this time, the first input terminal Nin1 is
opened, that is the first input terminal Nin1 does not receive any
signal).
Briefly summarized, in the receiver of the present invention, two
band groups are coupled to two input terminals of the double
balanced mixer via switches, respectively. Therefore, each signal
path always suffers the parasitic load of its own switch, without
being affected by the switch in another signal path, and the signal
quality and the performance of the band groups will become
better.
Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *